Verified family records are scarce in Ireland. Early censuses were accidentally shredded and pulped by the government and later censuses were destroyed in the 1922 Public records office fire. Catholic parish records, various land valuations (e.g. Griffiths), gravestone transcriptions and family histories are all that are left.

The Roots Ireland website is as authorative a source as remains and a search of its records for Kilkie, Kilky, Kilkey, Gilky and Gilkie find only a handful of records but in our view they are indicative.

Names found from pre 1800 are shown below

Birth	Gilkie	Charles	1683	Co. Derry
Church Marriage	Gilkie	James	1683	Co. Derry
Church Marriage	Gilke	William	1743	Co. Derry
Church Marriage	Gilke	Elizabeth	1744	Co. Derry
Church Marriage	Gilke	John	1744	Co. Derry
Church Marriage	Gike	Elizabeth	1745	Co. Derry
birth	Gilke	William	1746	Co. Derry
Church Marriage	Gilke	William	1746	Co. Derry
birth	Gilke	Elizabeth	1747	Co. Derry
birth	Gilke	John	1748	Co. Derry
Church Marriage	Gilke	Martha	1749	Co. Derry
Church Marriage	Giliky	Ann	1768	Co. Derry

Note that names change but they all start with G and not K. This is consistent with the original surname having the origin as Giolla. Also note that although the search was ireland wide all individuals are to be found in county Londonderry. It is not just the presence of names with a G it is also that there are no K surnames either that is so indicative that the name was Gilkie/Gilke/Gilky before it became Kilkie/Kilkey/Kilky.